Control system



May 4, 1965 R. B. STERNS ETAL CONTROL SYSTEM Filed Aug. 3, 1962 2Sheets-Sheet l DRIVE ROLLS 9 C UTTER ROLLS cw I ROLL I MOTOR I SPEE D i/7 CONTROL I PULSE GEN, -2

COUNTER REGISTER 23 -25 z; -27 2a 2? ME OR OR INVENTORS 05527 5 srm/vs wBY 00mm. J M/lf/O/VV HEEM/I/VG. MEYER, JR.

ATTO/QA/EVS' May 4, 1965 R. B. STERNS ETAL CONTROL SYSTEM 2 Sheets-Sheet2 Filed Aug. 5, 1962 3,181,403 CONTROL SYSTEM Robert B. Sterns, GreatNeck, and Donald J. Mahony,

White Plains, N .Y., and Herman G. Meyer, Jr., Newark,

N.J., assignors to Logic Systems, Inc., Great Neck,

Long Island, N.Y., a corporation of New York Filed Aug. 3, 1962, Ser.No. 214,679 10 Claims. (Cl. 83-76) This invention relates to theregulation of manufacturing operations and more particularly it concernsa method and means for improving the quality of manufacturing operationswith a decreased amount of regulatory control.

Regulation or control of a manufacturing operation is generally achievedby measuring a given characteristic resulting from the operation, andthen adjusting a control element according to the amount by which thisresulting characteristic deviates from a desired value. The controlelement modifies the operation in degenerative fashion to bring theoutput characteristic into conformity with the desired value. In orderto compensate adequately for changing environmental conditions, it hasbeen the practice to produce this control adjustment asquickly anddirectly as possible. Very often continuous automatic feed back controlis provided. In cases where this is not possible, such as inintermittent type manufacturing operations where individual items areproduced in successive operations, rapid adjustment has been produced byutilizing measurements obtained after one operation to reset the systemfor the next succeeding operation.

According to the present invention, instead of providing more and fasterfeedback control, improvement in regulation is achieved by providingless but more selective control. This improvement is based on the factthat the measured value of .a manufactured item at any instantrepresents the results of both controllable and uncontrollable variablesaffecting the operation. This is due to the fact that a certain amountof manufacturing tolerance exists for which no amount of regulatorycontrol will compensate. This occurs in all realistic systems and iscaused by such things as slippage, blacklash, flexure, etc., whereby fora given setting of the system performing the operation, the measureoutput quantity may take any value within a certain tolerance range.Manufacturing tolerances can be reduced, of course, with close controlof raw materials and improved processing apparatus, but the extent ofsuch tolerance reduction is limited by both cost and practicality.

According to the present invention, recognition is given to the factthat the uncontrollable variables represented in each output measurementoccur in random manner while the controllable variable, at least insofaras it is controlled, does not. Thus for many measurements taken over. along period of time during the occurrence of the manufacturingoperation, the measured quantities assume a statistical or Gaussiandistribution, the mean value of whichrepresents only the controllablevariable. By detecting this meansvalue and adjusting the control elementbased solely on its deviation from a desired value, a more accurate yetless active mode of control is provided.

In theory, an infinite number of individual measurements are required toascertain the precise value of the statistical mean. The preferredembodiment however, utilizes only a few measurements and compares themaccording to a prearranged program to obtain the most probable value oftheir statistical mean. This compari- United States Patent 3,181,403Patented May 4, 1965 son program is defined by setting a desired balancebetween speed of correction and accuracy of correction. Basically, itentails the comparison of the number of occurrences of measurements ofdifferent values. Whenever a preselected number of measurementsoccur ata given value, a corresponding correction is made. Means are furtherprovided to sense the rate at which the measured values change and tosuperimpose further correction based on this.

It is a general object of this invention to provide means for improvingthe regulation of manufacturing operations.

A more specific object is to provide such regulation based upon adetermination of the value of a controllable variable in the system.

There has been outlined rather broadly the more important features ofthe invention in-order that the detailed description thereof thatfollows maybe better understood, and in order that the be betterappreciated. features of the invention and which will form the hereto.Those skilled in There are, of course, additional subject of the claimsappended the art will. appreciate that the conception upon which thisdisclosure is based may readilyv be utilized as a basis for thedesigning of other structures for carrying out the several purposes ofthe invention. It is important, therefore, that the claims be regardedas including such equivalent constructions as donot depart from thespirit and scope of the invention.

A specific embodiment of the invention has been chosen for purposes ofillustration and description, and is shown in the accompanying drawings,forming a part of the specification, wherein:

FIG. 1 is a schematic illustrating a preferred embodi-v ment of theinvention; and

FIG. 2 is a diagram illustrating typical operating characteristics ofthe preferred embodiment.

The embodiment of FIG. 1 is shown as applied to control the operation ofa precision cut-off device.

of a pair of drive rolls'11 and 12 toward a pair of cutter rolls 13 and14. The cutter rolls have shear blades 15 extending from their peripherywhich sever the web 10 upon each complete rotation. Thelength of the.severed web pieces dependsupon the distance the web. 10 moves past thecutter rolls between successive operations of the shear blades. This inturn depends upon the ratio maintained between tional velocity ofthecutter rolls 13 and 14.

A constant speed drive roll motor rotate the drive rolls-11 and 12. The14 are rotated by means of a variable speed cutter roll motor 17 whoserotational velocity is a motor speed control device 18. is also providedbetween the drive Aweb driven roll 9 and cutter rolls. It

will be seen that'the cut length of each web piece depends cutter rolls13and 14.

upon the ratio of the speeds of the and the web driven roll 9. Thisratio is adjustable by means of the motor speedcontrol 18; As will bedescribed more fully, means are provided to detect the length of cut forsuccessive operations of the shear blades, andstatistical means de-.

present contribution to the art may.

that will be described hereinafter,

III device a continuous sheet or web 10 is driven .by means.

the linear velocity of the web 10 and the rota- 16 is provided .tocutterrolls 13 and.

varied by means of "Y! a a a o duced in any interval thus represents theamount of movement of the web ill in that interval.

each complete rotation of the cutter rolls l3 and M. This occurs whenthe shear blades come together to sever the web it It will be seen thatthe number of voltage pulses produced by the first pulse generator 19between successive pulses from the second pulse generator 26), providesan indication of the lengthof web material which has last been cut. a

j The output pulses from the first pulse generator 19 are supplied tothe input of a main counter-register Zll. The main counter-registerincludes a plurality of output terminals, designated as 22, whichrepresent diflerent numbers of accumulated input pulses. The particularoutput terminal upon which'a finite voltage appears at any given timeindicates the number of pulses which have been accumulated in thecounter at that time. Those skilled in the art will readily apprehendseveral possible arrangements of well known elements such as coincidencecircuits and bistable switches which can be' adapted to perform thesefunctions. In a preferred arrangement, the counter capacity would beadjustable between the point at which input signals are applied and theoutput terminals representing the highest count. This permits adjustmentof the automatic control so that different lengths of web may be cut.Inasmuch as variable capacity counters of this type are relatively wellknown, the counter is merely illustrated in block form and is shown tobe broken as at V to indicate its variable capacity. The

output pulses from the secondpulse generator 20 are directed via a pulsedelay means23 to a reset terminal 2d in the counter-register Zll.Thispermits the counter to be cleared upon the occurrence of each cut.Each web piece which is cut is seen to bemeasured by the number ofpulses stored in the counter between successive clearing pulses from thesecond pulse generator 20.

, While high accuracy in the measurement of the length of eachparticular cut will ensure greater accuracy in correction, it has beenfound expedient from the standpoint of both economy and reliabilitymerely to indicate each measurement according to which of several lengthzones it represents. The lengthzones may be established by controllingthe amount of linear distance traveled by the sheet material for eachpulse produced by the first pulse generator 19. Thus if each pulserepresents one inch of linear travel for the web, the fourth terminal toproduce a voltage represents a web movement or length of cut anywherefrom four to five inches. The length zones 7 may be adjusted as towidth'by interconnecting groups 0 of output terminals as shown in FIG.1.

According to' the preferred embodiment, five length zones have beenchosen and are designated respectively as the 28, 1S, tlK, 1L and 2Lzones. A length of cut occurring in any such zone produces a voltage ata corresponding pulse supply lead 25-29. By adjusting the count capacityof the main counter-register 21 so that a length measurement for adesired length of cut produces a voltage on the @K zone pulse supplylead 27, the zone arrangement is made to represent deviations of lengthsof cut from desired values.

A signal gating arrangement is provided to prevent the.

occurrence of voltage signals at the output ends of the pulse supplyleads during the count buildup in the main counter-register 23 betweensuccessive cuts. The signal gating arrangement includes a number of dualinput terminal AND circuits 36-34, each having one input terminalconnected to a corresponding pulse supply lead. The remaining inputterminal of each AND circuit is connected via a common lead to receivesignals .from the second pulse generator 20 upon the occurrenceof eachcut. The AND circuits produce an output signal only upon the coincidenceof finite signals at both inputs. Therefore output signals appear at theoutput of the signal gating arrangement only upon the occurrence of acut and A second pulse generator 29 is provided to produce a singlevoltage pulse for vice itself. In general, however, it may be said thattheirv relative capacities should be distributed to resemble aamplifiers ll-d l whiclnwhen activated by signals-from the capacityoutput terminals, generate correction voltages of prescribed magnitudeand polarity. Thecorrection voltages are applied via associated feedbacklines to adjust the motor speed-control means 18, in a degenerativemanner. This in turn changes the rotational speed of the cutter rolls ina manner to change the length of cut produced on the Web ill.

The signal storage elements may be conventional pulse counting devices.Theirindividual count capacities are set according to a number ofconsiderations including the speed and accuracy of correction desired,the number of zones and the tolerance characteristics of the cutting'destandard deviation curve centered about the 8K zone. Thus the countcapacities of the storage elements 37, T-h and 3?, in the 1S, tlK and lLzones, respectively, should be greater than the capacity of the storageelements 36 and it in the 2S and ZL zones. In the present embodiment, afour count capacity for the storage elements in the TS, 6K and TL zonesand a two count capacity for the storage elements in the 2S and 2L zoneswas found to produce good results.

An additional refinement is provided on certain'of the signal storageelements, namely those which receive signals occurring Within the 2S, 0Kand EL zones. According to this refinement, these particular storageelements continue to store signals only while successive measurementscontinue to produce signals which occur in the particularzonereprcsented by the element. Should a measurement subsequentlyproduce a'signal in a difierent zone, the first storage element becomescleared. This is accomplished by the provision of INHIBIT gate circuits47, ts and 49 in conjunction, respectively, with each of these threestorage elements. The INHIBIT gate circuits each include a first inputterminal 50 connected to receive signals from the second pulse generator2t), and an inhibit terminal 51 connected to receive input signals fromthe same AND circuit as its associated storage element. The INHIBIT gatecircuits are similar in construction to the AND circuits except thatprovision is made whereby an output signal is produced if-a signalappears at the first input terminal but not if another signal is beingreceived at the inhibit terminal. Suchcircuits are well known in thedigital computer field and typical examples suitable for use in thepresent environment areshown on pages 401-403 of the book entitled Pulseand Digital Circuits by Jacob Millman and Herbert Taub, published by theMcGraw-Hill Book (30., New York, 1956. The output signals from theINHIBIT gate circuits are applied to reset terminals 52 on theirassociated pulse storage elements 36, 38 and Each ofthese pulses storageelements continues to store signals as long as they continue to occur inthe zone represented by the element. However, should a length of cutsubsequently occur which produces a signal in another zone, no signalwould then be available at the inhibit terminal 51 of the INHIBIT gatecircuit to prevent an output signal from being produced by the pulsesupplied from the second pulse generator Ztl; and the storage elementwould then become cleared or reset by this signal being appliedatitsresct terminal 52. a V f v The output of each signal storage element,except that representing the tiK zone, is further connected throughassociated OR circuits the 1S and a correction is produced by theoccurrence of a signal I from a storage element capacity outputterminal, each of the other storage elements, except the K storageelement 38, becomes cleared to a zero count. The particular storageelement which becomes overloaded however, is not cleared and continuesto produce correction signals as long as measurement deviations occur inits particular zone.

The system thus far described is effective to ascertain with reasonableaccuracy the most probable location of the statistical mean deviation ofa small number of measurements. Very often however this mean itself maybe shifting beyond acceptable limits during the measurement period. Ithas been found that it signals occur in either the 28 or 18 zones withina certain number of measurements after having occurred in either the 2Lor the IL zones, or vice versa; the probability that the mean deviationis shifting is high enough to warrant immediate correction.

This detection of this probable shift is accomplished by providing apair of bistable switching elements such as flip-flop circuits 54 and55. Each flip-flop circuit includes a trigger input terminal 5 6, areset input terminal 57 and at least one output terminal 58. The voltagelevel at the output terminal at any time depends upon which of the inputterminals last received a voltage pulse. The circuit is consideredtriggered whenever this output voltage is finite, as when the lastapplied pulse occurred at the trigger input terminal 56; and isconsidered reset whenever this output voltage is zero as when the lastapplied pulse occurred at the reset input terminal 57.

The first flip-flop circuit 54 is connected by means of an OR circuit 65to be triggered as a result of input signals being supplied to eitherthe 28 or 18 signal storage elements 36 or 37. These signals are alsoapplied to the trigger input terminal/56 of the first fiip-fiop circuit54. Likewise, the second flip-flop circuit 55 is connected by means ofan OR circuit 66 to be triggered by signals supplied to either the 2L or1L zone signal storage elements 39 or 40. Each of the flip-lop circuitsis reset by the output from the signal storage element 38 in the 0Kzone; which occurs whenever at least four consecutive measurementsproduce signals in this zone.

The output terminal'of the first flip-flop circuit 54 is connected toone input terminal of an L zoneAND circuit 59 while the output terminalof the second fiip-flopcircuit 55 is connected to one input terminal ofan S zone AND circuit 60. Also the trigger input connection to the firstflip-flop circuit 54 is further connected to the remaining inputterminal to the L zone AND circuit 59 while the trigger input connectionto the second flip-flop circuit is further connectedto the remaininginput terminal to the S zone AND circuit 60. The output terminals of theS zone'and L zone AND circuits are connected respectively to the 1S andIL correction amplifiers 43 and 44.

In operation of the system, the web 10 is driven continuously by meansof the drive rolls 11 and 12, past the cutter rolls 13 and 14 where itis periodically severed by the shear blades 15 into individual lengths.

During this time measurement signals are produced in accordance witheach severed length. These signals are assigned on the basisof-indicated length to the various storage elements 36-40.Correctionsignals are obtained from the storage elements depending uponthe manner in which the measurement signal becomes distributed amongthem. These correction signals represent the most probable statisticalmean deviation froma desired value of the various measured lengths or,in some instances, the most probable shift in this mean deviation. Thecorrection signals are then used to change the setting of the motorspeed control-18, which in turn changes the rotational velocity of thecutter rolls 13 and 14 to afiect a length of cut adjustment for thesystem.

The various length measurement signals are produced in digital fashionto facilitate their assignment based on measured length to the storageelements which represent the various length deviation zones. Wheneverthe web 10 becomes severed by the shear blades 15, a front or leadingedge of a particular length is formed. When this occurs, the secondpulse generator 20 supplies a pulse through the delay means 23 to thereset terminal 24 which clears the main counter-register 21. As the web10 continues to move past the cutter rolls 13 and 14, a succes sion ofpulses, produced by the first pulse generator 19, are supplied at theinput of the main counter-register 21. Depending upon the calibration ofthe first pulse generator, the number of these pulses indicates thedistance which the leading edge moves past the shear blades 15. Theparticular number of input pulses applied to the counter since the lastprevious clearing pulse (and since the leading edge of the sheet beganto move past the shear blades 15), is seen in the particular one of theseveral output terminals 22 which is at a finite voltage. Since each ofthe output terminals is connected via an output lead 25-29 to acorresponding AND circuit 30-34, each AND circuit in succession receivesa finite voltage and thus becomes potentially capable of supplying apulse signal to an associated signal storage element 36-40.

The next subsequent operation of the shear blades 15 forms the trailingedge of the particular cut length. The pulse produced at this instant bythe second pulse generator 20 is immediately supplied to the remaininginput terminals of each of the AND circuits. This causes the particularAND circuit, which at the same instant happens also to be receiving afinite voltage from its corresponding input lead, to pass a pulse signalto its associated storage element. In order to allow the AND circuit todeliver this signal, the delay circuit 23 prevents clearing of the maincounter-register, and consequent removal of voltage from the AND circuitinput terminal, for a short time after the occurrence of the outputpulse from the second pulse generator 20.

The particular signal storage element receiving a pulse signal isdependent upon the number of counts which accumulate in the maincounter-register between the times it is cleared at the occurrence ofthe leading and trailing edge cuts. Since this number represents thelength of cut, the storage element, as stated previously, may beconsidered as representing a length zone, or in the present case, alength deviation zone.

As successive lengths are cut and corresponding measurements made in thefashion described, the various storage elements 36-40 accumulatediflerent numbers of applied signals. When the count in any storageelement reaches the capacity of the element, an output signal isproduced which activates a corresponding one of the correction amplifiercircuits 41-44 to produce a voltage of proper magnitude and polarity toadjust the motor speed control element 18.

The relative capacities of the storage elements are such that moremeasurements must occur in the zones of mod erate deviation (1S and IL),in order to produce a corrective signal, than must occur in the zones ofextreme deviation (28 and 2L). For any given setting of the motor speedcontrol element 18, the resulting signals over a long period tend toassume a Gaussian distribution among the signal storage elements. Thestorage element receiving the greatest number of applied signalsrepresents the mean value of this distribution. If the motor speedcontrol element is correctly adjusted, then the distribution shouldoccur among'the storage elements such that very little correction isproduced. If however the motor speed control element is incorrectlyadjusted, the distribution shifts. A large shift will be detectedquickly since the extreme deviation storage elements have low capacityagainst time.

II and signals will be most likely toioccur in these zones. Also anysignal obtained as a result of an output from these storage elementsproduces a large corrective signal in the 28 or 2L correction amplifier.Smaller mean de ment is to continue storage. Any signal produced in adifferent storage element causes clearing of these particular elements.This prevents large corrective signals from being developed should someunusual or erratic condition affect a single measurement without reallyinfluencing the long term effects of the cutting operation. I

By providing a means for clearing each storage element upon theoccurrence of each corrective signal, any distributional pattern whichthe signals assume among the various storage elements is made strictly afunction of a given setting of the motor speed control element. Thispermits a more accurate and faster determination of the most probablemean deviation and consequently more efficient system control.

While the distribution of the signals stored among the various storageelements provides an indication of the most probable mean deviation ofthe me sured lengths, it is conceivable that this mean deviation couldbe rapidly shitting during the time that measurements are beingobtained. This shift is best detected by noting measurements which shiftfrom one side of the lll zone to the other within a given number ofcuts. Whenever a signal is applied to a signal storage elementrepresenting the or it? zone, the trigger input terminal 56 of the firstlip-flop circuit triggers that circuit so that a finite voltage appearsat its output terminal $8, which voltage in turn is applied to one inputterminal of the L zone AND circuit mains in its triggered stateindefinitely and is reset only by an output signal from the signalstorage element 38 in the 6K zone. When a measurement signalsubsequently occurs in either the 1L or 2L zones prior to resetting ofthe first flip-flop circuit 54, a voltage signal' is supplied to theremaining input terminal of the second AND circuit 59. Since the firstterminalof this circuit has received a finite voltage from the firstflip-flop circuit 54, it produces an output which activates the ILcorrection amplifier 43, to produce an immediate correction signalindependently of the particular arrangement of signals in the variousstorage elements. A similar correction occurs in the opposite directionwhenever signals first occurring in the 2L or TL Zones are followed bysignals which appear in either the 28 or 18 zones prior to theoccurrence of four consecutive signals in the tlK zones.

A typical sequence of operation for the preferred embodiment is showngraphically in FIG. 2. Here the lengths of successive cuts, shown asdots, are plotted The length of cut coordinate in the plot is shown asbeing divided into five zones, designated respectively as the 23, 1S,6K, 1L and 21. zones. These coincide with the various length deviationzones represented by the various storage elements 36- 5% of FIG. 1.Although as shown in the diagram, the various cut lengths may take anyof several values within a zone, the system is arranged to operate onlyon the basis of the numbers of signals within the various zones and isinsensitive to the precise position of any signal Within a zone.

it will also be can from the diagram of FIG. 2 that the zones do nothave identical widths. The particular Width assigned to each zonedepends upon environmental situation to which the control system isapplied. In the Q, present case, it has been found that byeirpandingtlie 1L zone as shown, improved compensation is obtained forcutter velocity variations which occur when the system is turned on andoff. This is accomplished merely by connecting the pulse supply lead'ZEito a greater number of terminals 22 in the main-counter register 21. v

The arrows shown in the graph indicate the various correctionsintroduced by the correction amplifiers ii-dd. These four amplifiersprovide four different types of correction, two in magnitude and two indirection; each of whic, has been represented in FIG. 2. The variouscorrection indicating arrows are identified as A, B, C, etc..

The first correction A is of low magnitude and directed toward the Lzones. This correction is seen'to result from tour cut lengths producingsignals in the 18 zone storage element 37. This correctionoccurs eventhough the signals do not occur consecutively. Once the correction ismade however, the 18 zone storage element is reset and four more outlengths producing signals in the 13 zone must occur before the secondcorrective signal B occurs. The third indicated correction, C, is' alsoof low magnitude but in the opposite direction of the previouscorrections. This correction results from four out lengths producingsignals in the ill, storage counter 39. T he next subsequent correctionD, is of high magnitude and toward the 5 zones, and occurs as the resultof two consecutive signals accumulating in the EL storage element as. r

r The next correction E is of low magnitude and is directed toward the Szones. This correction is produced by signals occurring first in the 3Szone and subsequently in the EL zone. When signals shift from an S zoneto an L zone, and vice versa, within a given number of cuts, there is agreat likelihood that their mean deviation also is shifting and animmediate correction is provided irrespective of the number of countswhich may have accumulated in any of the counter elements. However,should 'four consecutive signals occur in the (HQ zone before completionoi this shift, an output signal from the 9K zone signal storage element33 operates to the ilip-ilopcircuits 54 and 55. This removes the voltagefrom one terminal of the L zone and S zone AND circuits 59 and 6t), andprevents correction signals from being applied through these circuits ifa signal subsequently occurs to complete the shift.

The remaining corrections may be seen to follow the same criteriaoutlined above. These criteria .may be adjusted as by changing thenumber of counter'register output terminals 22 connected to each outputlead 2529,

or by changing the various count capacities of the storage elements 36-28. The exact manner of adjustment to produce optimum results will, ofcourse, depend upon the particular application.

Having'thus described my invention with particular 7 reference to thepreferred form thereof, it will be obvious.

to those skilled in the art to which the invention pertains, afterunderstanding my invention, that various changes and modifications maybe made therein without departing from the spirit and scope of myinvention, as defined by the claims appended thereto. I

What is claimed as new and desired to be secured" by Letters Patent is:

1. Apparatus for controlling the length of cut produced by a cut-oildevice, said apparatus comprising, means for producing a continuoussuccession of voltage pulses having intervals representative ofincremental distances by which material to be cut moves with respect toa cutting tool, means for producing a further pulse upon the occurrenceof each cut made by said cutting tool, a main counter arranged to countthe successive pulses and to be cleared by'said further pulses, aplurality of signal storage counters having discrete count capacities,means for applying an input signal to one of said storage counters uponthe occurrence of each further pulse, the particular storage counterbeing selected according to. the number of pulses accumulated in saidmain counter at the instant of occurrence of each cut, each of saidsignal storage counters being arranged in isolation from the eilects ofthe pulses directed into other signal storage counters so that theaccumulated pulse count in each signal storage counter is unaffected bythe sequence of application of pulses to said signal counters, meansassociated with each storage counter to produce upon overload acorrection signal having an amplitude and direction which bears a givenrelationship to-the number of pulses required in said main counter tosupply an input signal at said storage counter, and means for adjustingsaid cut-off device to produce a different length of cut according tosaid correction signal. 7

2. Apparatus for regulating the operation of a manufacturing systemwhich successively imparts a given characteristic to individual items,said apparatus comprising, means for generating measurement signalshaving magnitudes representative of measurements taken of said givencharacteristic on several successively produced items, a signal sort-ingmeans operable to assign each measurement signal to a particular signalpath based upon the magnitude of the deviation of the signal from adesired value, signal counting means associated with each path andconnected to receive the signals applied to the respective paths, eachsignal counting means having a discrete count capacity and being capableof producing an output signal upon the reception of a number of receivedsignals in excess of said count capacity, said number being generallyinversely proportional to the magnitude of signal deviation from desiredvalue represented by its associated path, each of said signal countingmeans further being arranged in isolation from the effects of signalsdirected into other signal counting means so that the accumulated signalcount in each signal counting means is unaflfected by the sequence ofoccurrence of said measurement signals, means responsive to theoccurrence of an output signal from said signal counting means foradjusting said manufacturing system to change the magnitude of saidgiven characteristic, and means further responsive to the occurrence ofan output signal from one of said counting means for clearing the othercounting means.

3. The apparatus described in claim 2 further including means forclearing those signal counting means having the least count capacityupon failure of the particular signal counting means to receiveconsecutively occurring measurement signals.

4. The apparatus described in claim 2 further including means furtherresponsive to the occurrence of an increase in count in one pulsecounting means within a given number of operations of said devicefollowing an increase in count in a certain other counting means toproduce a further corrective signal.

5. The apparatus described in claim 2 further including a dual inputcoincidence circuit responsive to the coincidence of voltages upon eachof two input terminals to produce an output, a bistable switching meansactivated by the occurrence of a signal in one path to produce acontinuous voltage at a first terminal on said voltage coincidencecircuit, means for applying a voltage to the other input of said voltagecoincidence circuit in response to the occurrence of a subsequent signalin another path, and means for producing a further corrective signal inresponse to outputs from said signal coincidence circuit.

6. The apparatus described in claim 5 further including means fordeactivating said bistable switching means upon the occurrence of aprescribed number of signals in a third path prior to the occurrence ofsaid subsequent signal.

7. Apparatus for regulating the operation of a manufacturing systemwhich successively imparts a given characteristic to individual items,said apparatus comprising It means for generating measurement signalshaving magnitudes representative of measurements taken of said givencharacteristic on several successively produced items, a plurality ofsignal storage devices, signal sorting means intermediate said signalmeasurement generating means and said signal storage devices fordirecting each measurement signal into a different signal storage deviceaccording to the magnitude of deviation of such signal from a desiredvalue, each of said signal storage devices being,

arranged in isolation from the effects of signals directed into othersignal storage devices so that the accumulated signal count in eachsignal storage device is unaffected by the sequence of occurrence ofsaid measurement signals, means responsive to the accumulation in eachindividual signal storage device of a prescribed number of signals togenerate a corresponding corrective signal, means for directing suchcorrective signals to adjust a control element within said manufacturingsystem to change the magnitude of said given characteristic according tosaid corrective signal, and means for clearing said storage elements ofaccumulated signals in response to the occurrence of each of saidcorrective signals.

8. The apparatus described in claim 7 wherein said given number ofsignals is generally inversely proportional to the magnitude ofdeviation from said desired value represented by the signals in eachparticular signal storage means.

9. Apparatus for regulating the operation of a manufacturing systemwhich successively imparts a given characteristic to individual items,said apparatus comprising means for generating measurement signalshaving magnitudes representative of measurements taken of said givencharacteristic on several successively produced items, a plurality ofsignal storage devices, signal sorting means intermediate said signalmeasurement generating means and said signal storage devices fordirecting each measurement signal into a diflerent signal storage deviceaccording to the magnitude of deviation of such signal from a desiredvalue, each of said signal storage devices being arranged in isolationfrom the elfects of signals directed into other signal storage devicesso that the accumulated signal count in each signal storage device isunattected by the sequence of occurrence of said measurement detectionsignals, means responsive to the accumulation in each individual signalstorage device of a prescribed nu ber of signals to generate acorresponding corrective signal, means for directing such correctivesignals to adjust a control element within said manufacturing system tochange the magnitude of said given characteristic according to saidcorrective signal, means for clearing said storage elements signals andmeans further responsive to each particular corrective signal to rendersuch detection means unresponsive to signals which have occurredprevious to said particular corrective signals.

10. Apparatus for regulating the operation of a manufacturing systemwhich successively imparts a given characteristic to individual items,said apparatus comprising means for generating measurement signalshaving magnitudes representative of measurements taken of said givencharacteristic on several successively produced items, a plurality ofsignal storage devices, signal sorting means intermediate said signalmeasurement generating means and said signal storage devices fordirecting each measurement signal into a different signal storage deviceaccording to the magnitude of deviation of such signal from a desiredvalue, each of said signal storage devices being arranged in isolationfrom the efiects of signals directed into other signal storage devicesso that the accumulated signal count in each signal storage device isunaffected by the sequence of occurrence of said measurement signals,means responsive to the accumulation in each individual signal storagedevice of a prescribed number of signals to generate a correspondingcorrective signal, means for ment Within said manufacturing system tochange the directing such corrective signals to adjust a control ele-References Cited by the Examiner UNITED STATES PATENTS magnitude of saidgiven characteristic according to said n t r r 2,897,638 8/59 Maker.corrective signal, means for clearing said storage elements 3,008,13111/61 Einsel.

of accumulated signals 1n response to the occurrence of 5 10481751 8/62Taylor M 318*28 X each of said corrective signals and means additionallyresponsive to the occurrence of said measurement signals FOREIGN PATENTSWithin mutually displaced magnitude regions Within a 4 771 9/60 GreatBritain given number of said operations to produce a further correctivesignal. 10 ANDREW R. JUHASZ, Przmary Examiner.

1. APPARATUS FOR CONTROLLING THE LENGTH OF CUT PRODUCED BY A CUT-OFFDEVICE, SAID APPARATUS COMPRISING MEANS FOR PRODUCING A CONTINUOUSSUCCESSION OF VOLTAGE PULSES HAVING INTERVALS REPRESENTATIVE OFINCREMENTAL DISTANCES BY WHICH MATERIAL TO BE CUT MOVES WITH RESPECT TOA CUTTING TOOL, MEANS FOR PRODUCING A FURTHER PULSE UPON THE OCCURRENCEOF EACH CUT MADE BY SAID CUTTING TOOL, A MAIN COUNTER ARRANGED TO COUNTTHE SUCCESSIVE PULSES AND TO BE CLEARED BY SAID FURTHER PULSES, APLURALITY OF SIGNAL STORAGE COUNTERS HAVING DISCRETE COUNT CAPACITIES,MEANS FOR APPLYING AN INPUT SIGNAL TO ONE OF SAID STORAGE COUNTERS UPONTHE ACCURRENCE OF EACH FURTHER PULSE, THE PARTICULAR STORAGE COUNTERBEING SELECTED ACCORDING TO THE NUMBER OF PULSES ACCUMULATED N SAID MAINCOUNTER AT THE INSTANT OF ACCURRENCE OF EACH CUT, EACH OF SAID SIGNALSTORAGE COUNTERS BEING ARRANGED IN ISOLATION FROM THE EFFECTS OF THEPULSES DIRECTED INTO OTHER SIGNAL STORAGE COUNTERS SO THAT THEACCUMULATED PULSE COUNT IN EACH SIGNAL STORAGE COUNTER IS UNAFFECTED BYTHE SEQUENCE OF APPLICATION OF PULSES TO SAID SIGNAL COUNTERS, MEANSASSOCIATED WITH EACH STORAGE COUNTER TO PRODUCE UPON OVERLOAD ACORRECTION SIGNAL HAVING AN AMPLITUDE AND DIRECTION WHICH BEARS A GIVENRELATIONSHIP TO THE NUMBER OF PULSES REQUIRED IN SAID MAIN COUNTER TOSUPPLY AN INPUT SIGNAL AT SAID STORAGE COUNTER, AND MEANS FOR ADJUSTINGSAID CUT-OFF DEVICE TO PRODUCE A DIFFERENT LENGTH OF CUT ACCORDING TOSAID CORRECTION SIGNAL.